Shoulder protocol (MRI)

The MRI shoulder protocol encompasses a set of different MRI sequences for the routine assessment of the shoulder joint.

Note: This article aims to frame a general concept of an MRI protocol for the assessment of the shoulder joint. Protocol specifics will vary depending on MRI scanner type, specific hardware and software, radiologist and perhaps referrer preference, patient factors e.g. implants, specific indications and time constraints

Indications

Typical indications include shoulder pain, decreased range of motion or weakness as in:

• shoulder impingement
• rotator cuff injury
• calcific tendinitis
• adhesive capsulitis
• shoulder instability
• Parsonage-Turner syndrome
• Quadrangular space syndrome
• pectoralis tear

1.5 vs 3 tesla

Musculoskeletal examinations are generally done on both 1.5 and 3 tesla. They profit from the improved spatial and contrast resolution of 3 tesla. Postoperative examinations in patients with metallic implants, however, should be done on 1.5 tesla with metal artifact reduction sequence.

Patient positioning

• the patient is supine with the arm adducted in mild external rotation, for the normal examination
• optional additional ABER position

Technical parameters

Coil

Multi-phased-array coils are recommended.

• dedicated shoulder coil
• flexible coil or ring coil for ABER view

Scan geometry

• in-plane spatial resolution: ≤ 0.4 x 0.4 mm
• field of view (FOV): 120-160 mm
• slice thickness: ≤3 mm

Planning

A typical MRI of the shoulder might look like as follows:

• coronal oblique images:
  • angulation:  parallel to the supraspinatus tendon or scapular body 
  • volume: from subscapularis to infraspinatus muscle including the whole humeral head
  • slice thickness: ≤3 mm
• sagittal oblique images:
  • angulation: perpendicular to the supraspinatus tendon or scapular body
  • volume: from lateral deltoid muscle up to the scapular body
  • slice thickness: ≤3 mm
• axial images:
  • volume: from above the AC joint to the axilla
  • slice thickness: ≤3 mm

Sequences

The mainstay in musculoskeletal imaging are water-sensitive sequences, this can be achieved with conventional STIR or fat-saturated images or with intermediate-weighted images.

At least one T1-weighted sequence should be included to ease the assessment and interpretation of bone marrow and/or soft tissue lesions.

Standard sequences

Most indications for an MRI of the shoulder joint do not require any contrast media:

• intermediate-weighted (fat-saturated)
  • purpose: detailed anatomy, assessment of the marrow, the rotator cuff and labrum as well as evaluation for bursitis
  • technique: IM fast spin echo
  • plane: coronal oblique, axial, sagittal oblique* (option for improved characterization of the subscapularis muscle)
• T1-weighted
  • purpose: bone and/or soft-tissue characterization including the rotator cuff and capsule
  • technique: T1 fast spin echo
  • planes: coronal oblique, sagittal oblique* (option for evaluation of the rotator interval in suspected capsulitis)
• T2-weighted
  • purpose: bone and/or soft-tissue characterization,  assessment of muscular atrophy and fatty degeneration
  • technique: T2 fast spin echo
  • plane: coronal oblique
  • Some indications might benefit from an application of contrast media as inflammatory disease or tumors

Optional sequences

• T1-weighted C+ (fat-saturated)
  • purpose: for inflammatory  conditions like capsulitis, bursitis or in case of suspected tumor
  • sequence:  T1 fast spin echo
  • plane: axial, sagittal oblique

MR arthrography

Indications for MR arthrography of the shoulder include chronic shoulder instability, multidirectional instability, microinstability or suspected labral and/or biceps pulley injury.

• intermediate-weighted (fat-saturated)
  • technique: IM fast spin echo
  • plane: coronal oblique, ABER sagittal
• T1-weighted
  • technique: T1 fast spin echo
  • planes: sagittal oblique, axial
• T1-weighted (fat-saturated)
  • technique:  T1 fast spin echo
  • plane: coronal oblique, axial (option), ABER sagittal

Practical points

• in the shoulder, the protocol can and should be tailored to the specific indication or clinical question
• the examination will benefit if every plane is imaged
• a typical native protocol will contain 4-5 sequences
• in suspected nerve compression syndromes e.g. Parsonage-Turner syndrome the coronal and axial image stacks might need an increased field of view, and the sagittal stack might need to be increased
• likewise in  suspected pectoralis major or latissimus dorsi injury, the field of view needs to be positioned further caudal and increased and might require a different n set of coils